Researchers at the National University of Singapore have successfully demonstrated the phenomenon of quantum entanglement created using miniature equipment placed onboard a tiny CubeSat standard nanosatellite moving in a circular Earth orbit. The device, located inside the nanosatellite, is capable of generating pairs of entangled (coupled at the quantum level) photons, which in the future may become the basis for a faster and safer “quantum Internet”.
Quantum entanglement is a ghostly phenomenon that occurs when two quantum particles, due to a special effect, become closely interconnected with each other. A change in the state of any of the entangled particles instantly manifests itself in the form of a change in the state of the second particle, while these particles can be separated by an arbitrarily large distance. Quantum entanglement will operate even if particles are on opposite edges of our Universe, which raises several “uncomfortable” questions for classical physics.
From the point of view of Albert Einstein’s General Theory of Relativity, nothing in the Universe can move faster than the speed of light, but this rule, apparently, does not apply to information transmitted using quantum entanglement. At one time, this idea extremely upset Einstein himself, who called quantum entanglement “a ghostly action at a distance”.
Nevertheless, the paradoxical phenomenon of quantum entanglement has long been observed by scientists in the laboratory and even used in some places in practice. However, rather bulky equipment was previously used to create it, and now researchers from Singapore were able to complete the work to drastically minimize the entangled photon generator.
The new mini-satellite was called SpooQy-1, which is a direct reference to the famous and mentioned phrase of Albert Einstein. The device enclosed in it is capable of generating pairs of entangled photons by conducting the light of a blue semiconductor laser through crystals with nonlinear optical properties. Note that the SpooQy-1 satellite is not the first “quantum satellite” in history, this honor belongs to a Chinese artificial satellite called Micius, with the help of which quantum information has already been transmitted to a record distance.
But the SpooQy-1 nanosatellite is much smaller than the full-sized Micius satellite, which weighs 600 kilograms. The SpooQy-1 satellite belongs to the CubeSat class, its weight does not exceed 2.6 kilograms, and its dimensions are 20 by 10 and 10 centimeters. The creation and launch of this nanosatellite into space is a demonstration of the fact that it is now in our power to create small-sized, energy-efficient and reliable quantum technologies, because, as practice has shown, the SpooQy-1 satellite remains operational under significant temperature fluctuations and when other adverse effects cosmic factors.
“In the future, such systems can become part of a global quantum data network, interconnecting ground communication stations, and other spacecraft”, the researchers write. to the completely secure transmission of quantum data using the phenomenon of quantum teleportation”.